Tropos Metro Mesh is a system of nodes used in Tropos wireless networks for mission critical applications. The Tropos Metro Mesh routers have a set of security countermeasures employed so that when a node communicates with another node it can already ascertain whether the node is trusted or not. The Mesh routing protocol is designed for selecting optimal and best alternate paths for high throughput and low latency. While it is designed to react and respond quickly to disruptions and failures, it is not designed to detect misbehaving nodes.
In the dynamic environment of the Tropos mesh network (and similarly for other wireless mesh networks) where an increasing number of nodes are integrated and with a range of types of end users (Wi-Fi clients) using different types of services over the Tropos mesh network, there is also a need to establish trust that such mechanisms are working while allowing for the possibility to increase the resilience of the network to attacks.
Availability attacks and attacks on wireless mesh nodes are in general difficult to protect against as they are dynamic and may involve a coordinated and distributed effort to carry out. While wireless mesh networks implement security standards and a layered approach to security, the devices often operate in the public domain (unlicensed spectrum) giving threat agents the opportunities to find ways of bypassing security.
Existing mechanisms such as Intrusion Detection Systems (IDS) and Honeypots have a well-known problem of false positives, meaning a tendency to generate too many alarms, and making it hard to separate intended from malicious activity. There is a need for minimising the amount of false positives while building a good understanding of the behaviour of an anomalous node so that it is possible to more accurately detect whether a node is misbehaving.
The invention makes use of a reputation scheme based on previous work in J. E. Y. Rossebø, K. Hansen, K. McGrath and S. H. Houmb, “Towards a Framework for Evaluating Risk When Customer Premises Networks are Integrated in the Smart Grid”, in Proceedings of International Workshop on Risk and Trust in Extended Enterprises (RTEE'2010), November, 2010 and is also reusing the core concepts of the trust vector model from Indrajit Ray, Sudip Chakraborty and Indrakshi Ray, “VTrust: A Trust Management System Based on a Vector Model of Trust,” Proc. of the 1st International Conference on Information Systems Security, December, 2005 and Indrakshi Ray, Indrajit Ray and Sudip Chakraborty, “An Interoperable Context-Sensitive Model of Trust”, Journal of Intelligent Information Systems, vol 32(1) 2009 and extending the model with reputation evaluation procedures and behaviour analysis for trust monitoring and reputation building in the wireless mesh.
The Indian patent application IN2142/CHE/2008, describes a reputation based scheme in a wireless Ad-hoc network. The reputation scheme is based on passive mechanisms only to detect misbehaviour, such as by detecting packet discard. IN2142/CHE/2008 differs from the present invention mainly because it addresses Ad-hoc networking and that it only uses passive techniques to detect misbehaviour.
US2011078775 discloses a method where a combined trust value is computed based on local (i.e. node) credibility and a historical trust value stored in a trust server. US2011078775 does not combine the parameters in the same way as the present invention.
US2013315077 and US2013094398 show methods where an overall reputation is determined by a combination of multiple measured quantities, e.g. packet drops, delay, error rate etc. These documents do not combine the same parameters as the present invention.
In US2009328148, trust is evaluated for a group/cluster of nodes. The trust model works in three phases; at node level, at cluster-head level and at base-station level. US2009328148 does not combine the same parameters as the present invention.